Automatic firearm



l 1,628 226 May lo 1927' J. M. BRowNlNG AUTOMATIC FIREARM original Filed July 31.. 1923 s sneetsfsheet 1 liu Q nhPl .Nm o o o of@ o wo?@eQMMWNWWWWWMHF k v .mh rl .w N 151% @.VHQWOM J. M. BROWNING AUTOMATIG FIREARM May 10 s 1927.

original Filed Juiy 51, 1923 C i @MN M i www y Y mi Q mi Er di @d mv mi mun. @EN u i s Q A mv N B NM.. &\ n @im ww fww.) uw@ um .k @E

Patented May '10, 1927.

JOHN M. BaowNING, or oGDEN, UTAH; JOHN BRowN'ING ADMINISTRATOR or sein JOHN M. BROWNING, DECEASED.

.AUTOMATIC FIBEARM.

Application led July 31, 1923, Serial No. 654,955. Renewed Hay 15, 1926.

The invention relates generally to auto,- natic machine guns of that description in which all operations of the mechanism are automatically effected by the energy of the recoil of the movable parts.

The invention relates particularly to novel improvements in recoil-operated machine guns, smilar to that disclosed in the Letters Patent of' the Uniied States granted to John M. Browning. No. 1,293,021, dated February 4. 1919, in which the barrel and breech closing block. while inter-locked recoil together a limited distance, are then unlocked and the movement of the barrel is arrested; the breech closing block alone continues its re coil during which energy issored in reaction springs or similar means by which all parts are finally returned to their forward firing positions. 4

lT he main object of' the present invention is to produce a machine gun of this class specially adapted for modern military service. Experience duringthe war, and experiments since' under actual field conditions, have led the United States War Department to adopt for use in certain branches of the service, such as the. Anti-Air-Craft Service and for service in tanks, bullets 0r projectiles greatly increased in caliber, length and weight, and cartridge cases of increased size Capable of holding correspondingly increased charges of `most powerful explosivcs for driving said projectiles and for giving to them greatly increased rangesand power of penetration.

The machine gun of the present invention is adapted to fire these modern service cartridges; and while it has necessarily increased dimensions in diameter and length of certain of its parts, such as the barrel and breech mechanism, and of the lengthwise reciprocating movement of its breech opening and closing mechanism, these increases and the necessary strengthening of the entire structure of the machine gun are attained without a nearly proportional increase of the weight of saidmachine gun.

This object is attained by providing a composite-brake or buffer in rear of the heaviest recoiling members of the breech mechanism, Isaid brake consisting of the combination of a spring actuated recoil cushion combined with a brake chamber for j holding a liquid by which any excess of energy of recoil is entirely absorbed; and

by which even an excess of recoil, such as may pozsibly be caused by variations in the rate ofA speed of the ignition of the powder charges bythe primers'of the cartridges, will he absorbed without disastrous effect on the structure or the mechanism of said ma-a chine gun.

For furthering the attainment ofthis object there are also provided in rear of the breech closing block cushioning devices for absorbing any excess of energy of recoil of said breech block; as well as devices for strengthening the breech casing of the machine gun supporting .said cushioning de'- vices.

Otherand further objects and advantages will appear from the following disclosure.

kBy the foregoing and other novel con-y structions which will be hereinafter fully described and pointed out in the appended claims. an improved machine gunis produced, adapted for firing the modern powerful militaiyammunition, reliable, accurate, strong and absolutely safe under all conditions.

In the accompanying drawings:

Fig. 1 is a side elevation of the left-hand side of the gun, the forward portion of the barrel and of the tubular barrel casing being broken away.

Fig. 2 is a top view of the gun, the greater portion of the barrel and of the barrel cas-v ing being broken away.

Fig. 3 is a front end view of the barrel,

. of the tubular barrel casing and of the internal fixed disky closing said b arrel casing and guiding the muzzle of the barrel.

Fig. 4 is a longitudinal section of the foremost portions of the barrel and the barrel casing, and of the internal fixed disk.

Fig. 5 shows the pivoted switch lever, detached, respectively in a top view and in' a left-hand side view; it also shows similar views of the switch lever spring.

Fig. 6 is a rear end View of the gun.

Fig. 7 'is a rear end view of the gun with the rear plae removed, showing the breech casing and the mechanism therein.

Fig. 8 is a vertical transverse section through thev breech casing on the line 8-8 of Fig. 12, seen from the rear.

Fig. 9 is a vertical transverse section through the breech casing in the plane indicated bythe line 9-9 of Fig. 12, seen from the front and showing the forward end of feeding mechanism; members of the mechal nis'm attached'to the under side and to the top side of the top cover of the casing have been omitted. n

Fig. 10 is a vertical transverse section throuh the breech casing in the plane indicated by the line 10-10 of Fig. 13, seen from thefront and showing parts of the mechanisni for feeding cartridges and for ejecting the cartridge shells in 'their lowest position; members attached to the top cover hare been omitted, as in Fig. 9.

Fig. l1 4shows a rear portion of the barrel extension, detached, respectively in a lefthand side View, in a top View and in a rear end View.

Fig. 12 is a central vertical longitudinal section through the breech-casing, interior members of the mechanism and thc rear plate of the casing being shown in elevation; the barrel, barrel extension, and breech block are in their forward closed positions, the forward portions of the barrel and of the tubular barrel casing being broken away.

ig. 13 is a central vertical longitudinal Section through the breech casing and some of the members of the interior mechanism, the rest of said members being shown in elevation; the barrel', barrel extension and breech block are in their rearmost open positions, the forward portions of the barrel and of the barrel casing being broken away.

Fig..1i'is a top View of the breech block, detached, and of parts carried thereby.

Fig. 15 is a left-hand side view of the breech block and other parts shown in Fig. 14.

Fig. 16 is a front end view of the breech block, detached, showing 'the feed extractor and the shell ejector mounted thereon.

Fig. 17 is a rear end View of the breech block, detached, showing the sear and the cooking lever.

Fig. 18 shows the sear detached from the breech block, respectively in a rear end view and in a left-hand side view.

Fig. 19 is a' right-hand side view of the detached breech block.

`Fig. 20 is aleft-hand side View of the feed extractor, detached, and of the shell ejector pivotally attached thereto, on an enlarged scale; this figure also shows in connection with the side view of the feed extractor, a portion of the top cover of .the breech casing in longitudinal section and with parts mounted thereon for co-operation with the feed extractor; the feed extractor cam is also shown in this figure, detached and in a rear view.V

Fig. 21 is a front end View, on the same scale asFig. 20, of the feed extractor, de-

tached, and of the/shell ejector pivotally attached thereto.

Fig. 22 is a top viewof the combined breech block guide and brake body, with the rear portions of the adjacentgside walls of the breech casing in horizontal section.

Fig. 23 is a left-hand side View of said combined breech block guide and brake body.

Fig.`24 is a rear end View of said combined breech block guide and brake body, with the rear portion of the adjacent righthand side wall of the breechcasing in a vertical section.

Fig. 25 is a vertical longitudinal section through said combined breech block guide and brake body, showing the, interior mechanism and the interconnection of said mechanism with the barrel extension, the rear portion of which is shown in elevation.

F ig. 26 is a vertical transverse section, seen from the rear, of the brake tube, detached from the breech block guide, said section being taken slightlyJ forward of the closed integral rear end ofsaid tube, showing the interior of said tube and a rear view of the 'compound piston therein.

Fig. 27 is a side view showing the dei ached brake tube with the compoundpiston therein, the piston rod extending in front ot' said tube through the se arated flanged diaphragm which norma y serves to vclose the forward end of said chamber. The piston rod is surrounded by a. helical buffer spring, the rear end of said spring resting against the face of said diaphragm with the forward end of said spring bearing against a front `bearing Washer.

Fig. 28 is a front end view of the combined guide and brake-body and associated parts.

Fig. 29 shows the spring-supporting washer, detached, respectively in a front view and in a bottom view.

Fig. 3() shows the rear disk of the compound piston, detached, respectively in a rear view and in a. left-hand side View; vthis figure also shows one of theT-shaped pins carried by said disk, detached and in two views.

Fig. 31 shows the forward disk of said piston, detached, respectively in a rear view, in a central vertical longitudinal section, and in a left-hand side View.

Fig. 32 shows the piston rod, detached, respectively in a left-hand side View, in a front end view and in a partial top View.

Fig. 33 shows4 the flanged, threaded diaphragm, detached, respectively in a front view, in a left-hand side View, and in a ccntral vertical longitudinal section. l

Fig. .34 shows the stuiing box gland for said diaphragm, detached. respectively in a front view and in a central vertical longitudinal section. e

`Fig. 35 shows a washer for the compression of the packing in the stuffing box in views similar to those in Fig. 34.

left-hand side view, in

1,628,226" s i f Fig. 38 shows, on an enlarged scale, the

vertical pin forming the rear abutment for the main spring and the integral horizontal arm carried at its upper end by said pin, detached from the breech block, in a top viewy and in a left-hand sideview; the side view 1 shows said vertical pinin its relation to the main spring and also shows the transverse -pin forming the forward abutment for said spring.

Fig. 39 shows, on the same scale as Fig. 38, the compound firing pin, assembled, re-

spectively in a longitudinal vertical section,

1n a front view, 1n a rear v1ew and 1n several transverse sections. v

Fig. 40 shows therear'part or body of said firing pin, detached. respectively in a top view, in a front View and in -a rear view.

Fig. 41 shows the forward pointed portionA l of the firing pin, detached, in a top View,

in a front view and in a rear view.

Fig.' 42 is a. front View of the rear part or body of said firing pin, detached, with the transverse pin seated in its position therein to serve as the forwardabutment for the main spring.

Fig. 43 shows a flat spring in the same ,position in which it is shown in Fig. 22,

but detached, and' it also shows a top view of said spring.

Fig 44 shows 'the nut for limiting the rearward movement of the rear piston disk, detached, respectively in a rear view, in a side view and in a front view.

Fig. 45 shows, detached from the breech block guide, the spring pawl for holding the liquid brake in adjusted position, which pawl has an integral forward extension for cao-operation with the accelerator, respec-c tively in a left-hand side view and in a rear view. I

Fig. 46 is a horizontal, longitudinal section of portions of the rear plate and of the right-hand-side wall of the breech casing, showing the co-operative relation between these parts and the reaction spring guide rod, seen from above.

Fig. 47 shows theI cooking lever pivot pin, detached, in a side view and in a rear view.

Similar numerals refer to similar parts throughout the several views.

The machine gun represented in the drawings comprises the following main parts.

The casing 1 enclosing the' breech mechanism is rectangular in form or cross section; and its two strong vertical side plates are, at the front, firmly attached by. rivets at a number of points to the frontiblock 2 of the casing. T o further unite the sides of the breech caslng, with said front block, a series of strong transverse' rivets has been addedv in a plane parallelxto the axis of the gun but a distance below it with their centers-preferably distributed in said planeythe fore'- most rivet being some distance'in rear of the face of said block 2, and the rearmost one bein near the rear end of the rearward extension of said block. VFor some distance in rear of said block 2, the,breech casing is downwardly open at la. for the ejection'of the cartridge cases.

As shown in Figs.l 1, 12, and 13, the real' so i half of the breech casing is offset, being extended downwardly, thereby providin a greater depth of s aid casing to accommo ate certain elements of the novel improved confa correspon ing longitudinal exterior groove near its bfottom, so that the bottom plate can only be placed in position beneath the breech casing by being .slid forwardly thereunder, thereby vertically interlocking said plate with said breech casing. In order to interlock them also longitudinally, the flanges are permanent-ly tied to the casing by a' series of strong rivets through each of the flanges and each of the side plates.

l In a similar manner, the top lof the casing 1 is closed, for some distance forward of its rear end, by a permanently fixed top plate 4 which extends oneach side beyond the casing and carries on each side a strong downwardly projecting flange clasping the outside of the casing. On each of its flanges, the top plate 4 is lprovided in its entire length with an inwardly projecting longitudinal rib, and the side plates ofl the casing h ave each a corresponding longitudinal exterior groove near its top, so that the top Y plate can only be placed in position above said breech casing by being slid forwardly thereover, thereby vertically interlocking said plate with said breech casing. In order to interlock them also longitudinally, the fianges are permanently tied to the casing by a series of strongy rivets through each of the flanges and each of the side plates.

As the best of steel is employed for its production, and with the construction hereinabove specified, the breech casingfhasbeen given the form of a very strongrectangular hollow steel beam, all partsof which are rigidly and permanently fixed together a'nd thus best adapted to resist the strains to which they are liable to be exposed by the firin of the powerful modern ammumtion hereinbefore described. This construction makes the breech casing in this resent case4 much superior in strength over t ose of ma` chine guns as heretofore produced, because, in the latter, the parts composing the breech casing are but lightly interconnected and are liable to yield under the strains due to the firing of the modern powerful ammunition.

Though the strength of the breech casing has been greatly increased, as explained, its Weight has been increased much less than proportionally.

The forward portion' of the breech casing 1 is closed at the top by the cover 4 which is pivoted at its forward end to the block 2 by a transverse -pin 4"; this cover, when lowered to the closed position, rests upon the top ofthe casing and, extending on each side beyond the casing, has two downwardly projecting fianges which clasp the casing, as shown in Figs. 1, 2, 9 and 10. In Fig. 1,

.the forward portion of the top cover is shown, in dotted lines, turned fully forward; in Fig. 12 it is similarly shown turned forward, but, in addition, it is also shown in an intermediate position between its closed and its fully forward positions.

The top cover 4a is locked in its closed position by the latch 12 carried thereby and rotatable in a forward direction on its hori' zontal transverse pivot pin located beneath the rear end of said cover, said latch being held in its cover-locking position with a shoulder thereon engagingl under the forward end of the fixed top plate 4 by the spring 12. See Figs. 12 and 13. In Fig. 13, the forward portion of the latch 12 and its spring 12a are represented by dotted lines,- because said parts are covered by a longitudinal cam 51 located on the lower surface of the cover and on the left-hand side of said latch 12 and its spring 12a. In Fig. 12,

. the forward portion of the latch 12 and the by ribs 5, 'see Fig. 2, on its respective sides fitted into corresponding grooves in the respective side plates of the breech casing.

It must be obvious that the hereinbefore described fixed, rigid and permanent interconnection of the side plates of the casing 1 ,by means of the anged bottom plate 3 and plate 4 and by the rivets anges and side plates, is of In machine guns the flanged to through said the greatest importance;

yas 'heretofore produced in which the parts composing the breech casing are but lightly ing the recoiling members of the reech mechanism in their rearmost position and also of absorbing any strain due to an excess of recoil, cannot perform these most important functions if, y bending or laterally yielding outward, the side plates should fail to support the rear plate in its operative lowestposition, thus making it and the re coiling members in the casing liable to be thrown violently rearward out of the un.

By the present construction, such ben ing or lateral yielding of the side plates is positively prevented by thc fixed, rigid and permanentinterconnection hereinbefore described.

Centrally on the rear face of theplate 5 av strong circular hub is provided for supporting the tube 6 in which a shouldered plunger for cushionin the breech block is located,- said plunger being forwardly supported by an inward shoulder in said hub. The tube 6 is closed at its rear end by a screw plug between which and said plunger is arranged an elastic packing, the effectiveness of which may be varied by adjusting said' plug.

At the top the rear plate 5 has a forwardly projecting transverse fiange which fits into a recess in the to plate 4, see Figs. 2 and 12, the upper sur ace of said flange lying in the same plane as that of said plate 4.

Projecting rearwardly from its rear face, the plate 5 has two strong transverse double flanges 5l, one at its top, the other near its bottom, see Figs. 1, 2, 6, 12 and 13. -The spaces formed between the parts of the respective flanges are adapted for receiving respectively upper and lower handle plates 7, which, when thus located, are rigidly secured by suitable means to said fianges and extend `laterally and rearwardly outward from the plate 5 and serve for lthe attachment to them of the two strong vertical handles 8. These handles 8 are adapted to be grasped by the operator of the machine gun for giving tothe same the necessary elevations or depressions' and the desired lateral training in aiming the gun.

Centrally between the handles 8 and just below the top portion of the upper double flange 5b of the rear plate 5, the trigger 9 of `the gun is mounted upon a transverse pivot Below and forward of said pivot` pin 9a. pin 9a a downward and forward extension serves to connect said wtrigger operatively with the firing mechanism.to be described.

interconnected, the rear plate, which must perform the functions of securely support- A -small helical spring is seated between a shoulder on said trigger extension and the under side of the forward flange on -said rear plate 5, whichA spring serves to yleldmg- 1y keep said trigger 1n its inoperative position. The outside rearmost portion ofthe trigger 9 extends downward and is made of y a sufficient width to adapt it for being operated, at will, for `firing the gun by either thumb of the operators hands graspmg the handles 8 and by exerting downward pressure upon the top of the trigger.

As shown in Figs. 1, 6, l2 and 13, centrally at the bottom of the rear plate 5 the locking latch l1 is seated therein on a transverse pivot pin. The lower end of sa-id latch has a rhook-shaped forward extension which takes a positive and secure hold underthe rear end of the bottom plate 3 of the casing, thereby locking the rear plate 5 vertically in its seat. Said latch 1.1 has also a rearward extension the under side of which is serrated and forms a finger piece by upward pressure against which the latch 11 may be turned rearward and upward, thereby releasing its hold on the casing and freeing the rear plate 5 for upward removal from the same. A small helical spring is seated within the latch 11, its loweri end resting upon the bottom of its seat in said latch, its upper end bearing against the -lower handle plate 7 thus serving to return said latch to its operative locking position whenever the rear plate 5 is returned to its lowest position; to permit such return of said plate the lowest forward portion of said latch is inclined forwardly.

and upwardly. It will be observed that the construction is such that the operator can release the latch and by continuing the upward movement of his hand remove the rear plate.

The barrel' 13 is slidably supported near its rear end in the front block 2 and extends forwardly therefrom through the cylindrical tubular barrel casing 14, in which its forward end is lengthwise movably supported as shown in Figs. 3 and 4, by the disk 14a fixed in said barrel casing, preferably by indenting the metal of the barrel casing into an annular groove formed in the periphery of said disk. The tubular barrel casing 14 is forward extension of the front block 2 to which the rear end of the barrel casing 14 is secured, is a second cylindrical threaded portion, of somewhat larger diameter, of the front block 2. This serves to provide the seat for a ring 2u which bears on each of its sides a trunnion projecting at right angles tothe axis of the barrel and thus adapting this machine gun to be, at will, mounted upon a gun mount provided with suitable trunnion boxes.

In order to further adapt this machine gun to be, also at will, mounted upon another niount of different construction, a transverse pivot hole 2b is provided through the side plates and the front block 2 of the breech casing 1 adjacent to the front face and the bottom side of said casing and the 'bottom plate 3 has depending from it, adjacent its sides, lugs 3 provided with transversely aligned perforations adapted to receive a transverse pin of themount (not shown). t

For the same purpose for which the openings in the barrel casing are made, the front block 2 also is provided with large openings for the free entrance of the cooling air. As shownin Fig. l, two circular air openings penetrate both the side plates and the block 2; and, as shown in Figs. 2, 12 and 13, a

similar circular air opening is provided through the top of the block 2. A co'nsiderably larger opening lis made downward through the block '2 below the barrel. The location of these vertical and transverse openings is such that it coincides with that portiony of the barrel most exposed to become heated by the tiring of the gun, being ]ust forward of the firing chamber. Between the rear end of the said large downward opening through the front block 2 and the shell ejection opening of the breech casing hereinbefore described, an integral portion of said block 2 remains below the barrel to support'and guide the same in its recoil and counter recoil.

The usual barrel extension 15 is adjustably secured to the breech end of the barrel 13. The barrel extension comprises two separated side members 15b with a transverse front connecting member 15c which receives and is connected to the end of the barrel and. with a rear transverse connecting member 15d. The two side members at their outer surfaces are in contact with or at least immediately adjacent the side plates 1 of the casing. F or some distance forward of their rear ends the said side members of said barrel extension have downward projecting portions of considerable length` and depth, the offset rear half of the under side of the breech casing hereinbefore described providing space above the bottom platel 3 for receiving said portions, see Figs. 12 and 1. The bottom plate 3 of the breech casing has on 1ts upper surface in rear of the ejection opening 1a of said casing, a wide, central, upwardly projecting rib 16, and said rib is T-shaped, being widest at the top; the lowest part of said downwardly projecting portions of the side members of the barrel extension are slotted to lit over said rib 16 on the bottom plate 3. Said T-shaped slot extends lengthwise through the entire downward projecting portions of the side members of the barrel extension, and the shaped rib 16 o n the bottom plate is as much longer than said projecting portions as is necessary to guide the latter in their entire lengthwise movement.

Y The breech block 17 is supported and guided between the side members of the said barrel extension y15 for longitudinal movement to open and close the breech of the barrel. The breech block 17 has longitudinal ribs 17 b at its sides engaging corresponding grooves in the side members of said barrel extension. Said breech block is locked in its forward barrel-closing position by a verticallysliding locking block 58 which is located in a corresponding mortise in the rear portion of the barrel extension 15.

For efecting'the upward locking move-l ment of said block 58 a. central longitudinal upward projection 16a is provided on the top of the bottom plate 3 of the breech'casing, the vertical forward end of said projection being some-distance in rear of the forward end of'the T-shaped rib 16. The said projection 16a extends rearward some distance and ends in a cam formed by an incline iu rearward and downward direction. During the last of the forward movement, or counter recoil, of the barrel 13 and barrel extension 15, with the breech block 17 therein, also in its forward position, the depending lower end of the locking block 58 is engaged by said inclined cam and forced upward, thereby positively "locking said breech: block in its forward position in said barrel extension and thus securely closing and locking the chamber in the breech of the barrel, See Fig. 12.

During the rearward movement or recoil of the barrel and barrel extension with the breech block therein, after firing a shot, the lower end of the locking block 58 is carried rearward beyond the inclined cam on the projection 16a, in which position said locking block may be lowered from its breech block locking position to its inoperative position.

The lower portion of the breech block 17 in its forward locked position, see Fig. 12, is almost en tirely contained between the side members of the barrel extension 15, but in its open rear position, see Fig. 13, the greater part of its length projects beyond the rear of the barrel extension, the rearmost'I downwardly projecting portion of the breech block then resting upon and being guided the breech block contacts only at its forward and its rear ends with guiding surfaces, the

breech block may be moved to and from said position with a minimum expenditure of force, comparatlvely a small amount of fricv tion having to be overcome.

In order to permit, by the lowering of the locking block 58, the unlocking of the breechL block 17 for movement in the barrel extension 15, said -locking block 58 is provided with a transverse'pin, 58, the ends of which project from the sides of said locking block into corresponding vertical slots through the side members of the barrel extension, thereby keeping the locking block in its seat in the barrel extension while allowing it the necessary vertical movement. To effect the lowering of the locking block 58, the breech Y block `guide 18 in rear of the barrel extension is provided with two horizontal armsl 18a projecting forwardly from its vertical side walls and rigidly connected therewith,

said arms lfitting linto corresponding horizontal grooves in the outer sides of said barrel extension which cross the vertical slots therein. The breech block guidev 18 and the arms 18a thereof are stationary in the breech casing jand the forward ends of the arms 18 are provided with downward and rearward, inclined surfaces forming cams. These ico cams engage the laterally projecting ends of the transverse pin 58a during the last portion of the recoil 4or rearward movement of thebarrel extension 15 and force said locking block 58 downward fromthe locked to the unlocked position and keep the same therein. See Figs. 12, 13, 22, 23, 25 and 28.

In Fig. 11, the rear portion of the barrel vextension 15 is represented, on a reduced scale, respectively in a top view, in a side view and in a rear view, the top view and the side view of this Fig.- 11 clearly show the vertical mortise for the locking block, the

top view, the side view and the rear view alll show the'vertical slots for the transverse lues its movement in the barrel extension 1 5.

Preferably in order to insure the movement of the breech block through a sufficient dis/ tance a supplemental impulse is transmitted to it by an accelerator 35, which is mounted on a-stationary pivot at the rear of the barrel extension 15. -The barrel extension, during its recoil, turns the accelerator 3 5 on its pivot, and thereby causes the 'tip of said accelerator to engage a projection on the bottom of the breech block 17 and to throw the same to the rear at an increasing rate of speed.V Said increasing rate of speed is caused'by the pressure of the rearface of the barrel extension against thepcu'rved forward surface of the ,accelerator 35, the point of contact between said parts lying, at-rst, at said tip of the acce1erator ,.but progressively moving nearer to the ,centergo the ac- 'celerators pivot, as clearly shown in Figs.

12 and 13. The impulse transmitted to the ybreech block 17 by the accelerator 35 cari ries it to its open rear osition,^ an excess of spring 36, see Fig. 12.

of recoil of said breech .b ook 1.7 be- 2| a orbed by the cushioning means here ifore described reinforced by the reaction- The great length of the cartridges for the use of which the present machine gun is adapted necessitates a lon breech block and an opening movement of t e same somewhat longer than the cartridge, as obviousl 'lengthwise movement of the breech bloc must include the clearance necessary for the downward movement of the cartridge follow'- ing the lengthwise movement of the block; It is to insure this considerable lengthwise movement that the accelerator provided.-

l The cartridges are very powerful. and the barrel, barrel extension and breech block must therefore be of considerable size and strength and of considerable weight in order tension during the counter recoilmovement,

and I therefore combine with the braking devicel a suitable resilient device such as a spring.

The-energy absorbing means or mechanism which is provided is located immediately at the rear of the barrel and .barrel extension,

which is normal] and preferably below the path of movement of t e breech block. This arangement of parts brin s the ener absorbing mechanism close tot e parts with which it is' directly associated and also avoids any interference with thefree movement of the breech block.

Preferably the energy` absorbing mechanism is constructed as a self Icontained unit held in fixed position in the casing, but w ich is capable of being removed therefrom. The removal of this mechanism is preferabl effected through the opening at the` rear o the casing and the cover 5 holding t "e energy absorbing mechanism in place. The energy absorbing mechanism while normally connected with the barrel ex- In order that detachment may be readily effected I preferably provide a constructionv which permits these parts to be detached by a relatively lateral movement when they are lremoved fromth'e casing.

The before-mentioned breech block guide member 18 is preferably made hollow or tiibular'and serves as a carrier or casing for the energy absorbing mechanism.

The said guide member 18 fits between the sides of the breech casing with its 'flat bottoni resting upon the bottom plate 3 of the same, while its flap top guides and su ports the breech block 17 and itsrear en rests against the rear plate 5, see Figs. 12 and 13. The member 18 is preferably provided with a longitudinal bore which forms a liquid receiving chambei'and a piston is provided which is longitudinally movable in they chamber. Connected with the piston is a piston rod 23 which is adapted to be connected at its front end with the barrel eX- tension 15. Preferably as already stated, the connection is such that the parts can be readily disconnectedV by a relative lateral moyement when they are removed from the casing. i

As shown and as preferred the barrel extension has connected with the portion 15c thereof a central rearwardly projecting arm y26. The forward portion of said arm nearest the barrel extension corresponds in width with a central vertical lopening in the-accelerator 35. thereby'allowing'said accelerator to freely move independently of said arm. At the rear of said forward portion the arm 26 has a lateral downward shoulder.

A being considerably increased in width and height', and in front of its rearmost portion said arm 26 has a .further downward extension which provides a means of connection with a head 23a on the piston rod 23. The

said head 23n carries an upward rejection which interlocks with the said ownward projection on the arm 26, see Figs. 13, 25 and 32. It will thus b seen that the parts are connected for longitudinal movement but that they can be readily disconnected by moving the piston rod 23 and the. head-23* transversely of the arm 26.

A washer 27, guided in the cylindrical bore of the breech block guide 18, surrounds the rear portion of the head 23a of said piston rod 23, said washer being held against independent rotary or forward movement on vthe head 23a by radial projections 28 on said head and corresponding recesses 28a in the 29; and the rear portion of said diaphragm` is threaded and screwed firmly into thevcor respondingly threaded forward end of a cylindrical brake tube 21 fitted in the some-` what enlarged rear portion of the bore of the breech block guide 18.y A central flange on the diaphragm 29, having adiameter approximately equal to that of the outside of the brake tube 21, is located between the forward end of said brake tube 21 and the,

shoulder formed in thebreech block guide 18 by the enlargement in the rear portion of the bore. l The front view of the diaphragm 29, see Fig. 33, shows two shallow holes on opposite sides of the axis of the diaphragm for the projections of a spanner wrench to serve for screwing said diaphragm into the forward end of the brake tube 21. f

To insur .a tight lit of the sliding piston rod 23 in tie diaphragm 29, the diaphragm is counterbored and provided with a stuffing boX 24. The front of the stuffing box 24 is closed in the usual manner by a gland, such,

for example, as the one 24a shown in Figs. 12, 22, 27 and 34, and the space in rear of said gland is occupied by a suitable packing forced into said stuffing box by the gland.u At the rear of said packing a thick washer 24h is mounted on the piston rod 23, and in rear of said `wash/er a strong helical spring 24c is seated, lits forward end pressing against the washer and its rear end resting against the rear wall of the stuffing box 24 in said diaphragm 29, see Figs. 13 and 25. By this construction and arrangement of these parts, and by making the opening in the washer conical, inclining forwardly and outwardly, the pressure of the spring 24 causes the washer to compress the packing inwardly tightly against the piston rod 23.

The cylindrical brake tube is closed at the rear by an integral rear end, the forward end being closed by the plane rear wall of the diaphragm 2f). The piston rod 23 eX- tends through the diaphragm into this chamber and carries at Aits rear a. piston f adapted to move longitudinally in the chamberwitliin the tube.21.f

In the operation of the device fluid is. al-

lowed to pass from one side of the iston to the'fother to retard the movement o' the pismovement upon said piston rod 23 and a rear disk 32 mounted vfor limited longitudi: -nal as well as rotary movement on said rod, see Figs. 25 and 26.

ln Fig. 3l, the forward disk 22 is shown, detached, in a side elevation, in a central vertical section, and in a rear end view; and inFig". 30, the rear disk 32 is shown, detached, in a side elevation and in a rear end view. Y

The forwnrddisk 22 has a hub 22Il projectingfrom its rear face, and said hub is provided with a threaded bore adapted t`o`- be screwed upon the correspondingly threaded rear end of the piston rod 23, see Fig.

A pin 31,' is driven into avtransverse I hole in said piston rod 23 leaving its ends projecting from said piston rod. The hub 22.*l of the forward disk 22 has a slot 22" in its rear end for receiving the. portions of the projecting pin 31 nearest to the piston rod 23 when said disk 22 is mounted on the piston rod 23, thereby preventing the disk 22 from either rotating or moving lengthwise on the piston rod 23; the projecting ends of said pin 31 extend beyond said hub 22. This disk 22 has two oppositely located segment-shaped recesses 22C.l

As shown in Fig. 30, the rear disk 32 also has two oppositely vlocatedsegment-shaped recesses 32a in its periphery, and it has a smooth circular central opening, which is large enough to allow said disk 32 to be quitev loosely mounted uponL the hub 22a of the forward disk 22. I provide means whereby relative rotation can be effected between the'two disks so as to cause the said openings or recesses of one disk to overlap those of the other to a greater or less extent an'd thus vary the rate of flow of the liquid from one side of the piston to the other as the piston is moved. The means for effecting this relative rotation is preferably operable frorn the exterior of the chamber thus making it possible .to elfect the adjustment without o ening the chamber and losing the liqui contained therein. The specific means which I prefer and have shown for effecting the relative rotation will now be described. On its rear surface the disk 32 has, near its edge, two oppositely located' raised projections. Centrally in each of `those parts in the edge of the disk 32 thickened by said projections,

rotation of said disk; as repl'esnted in Fig.

30, preferably each of said pins is provided at its outer end 'with a T -shaped flat head fitted into a corresponding longitudinal groove cut into the edge Jf said disk 32 transversely to the pin seat, thus forming a spline stronger for preventing rotation than the in would be without the head in Fig. 30 t e pinsprovided with heads 32", are shown seated in thedisk 32, an one of said T-shaped pins` 32b is also shown detached.

In Fig. 26, the compound piston is represented, as seen from the rear, seated in the liquid chamber of the brake tube 21, said brake tube being shown in a vertical transverse section taken in al plane slightly forward of the integral rear end of said tube. The two pins 32" on the rear disk 32 are there .shown with their T-shaped heads seated in two corresponding grooves in the interior surface of the brake tube in which, therefore, 'said disk 32 is 'prevented Jfrom rotating independently; but when the brake tube 21 Iis rotated in the'breech block guide 18, the rear disk 32 of the compound piston is compelled torotate with said tube 21. It will thus be seen that when the tube is rotated in the manner to be described the rear disk 32 is also rotated, thus causing the openings 32 to overlap the openings 22 to a rrreater or less extent and thus vary the brakmg action. In Fig. 26, a nut 33 is shown screwed upon the threaded rear portion of the hub 22a on the forward disk 22,

said nut serving to limit the movement in' rearward direction of the rear disk 32; this nut is locked in position against rotation and consequent longitudinal movement on said hub 22a by the pin 31, the ends of which are received for the adjustment of said nut 33 in either of two corresponding grooves in the rear face of the nut, said grooves being semi-circular at their innerA ends and slightly deeper than the radius of the pin 31. y

In Fig'. 25, and in the front and side views of Fig. 44 are shown two' wide grooves 33a cut into the forward surface of said nut 33. The forward movement of the piston simultaneously with the forward movement of the barrel and barrel extension, requires the free passage of the liquid from the front to the\ rear of the piston in the liquid chamber, and this free passage is attained by the co-operation of a series of holes 22d in the forward disk 22, .of th large central hole in the rear disk 32, of

the grooves '33 in the lnut 33 and of-.the

'segment-sha ed recesses22 and 32'* in said forward an rear disks, respectively. j A

It will be seen that during the rearward movement of the piston the disk 32 is in contact -with the d1sk22 thus entirely closing the holes .22, but'thatduring the forward movement of the piston the disk 32 is slightly separated from the disk 22 thus permitting the liquid yto pass freely through the said holes'22d and `between the disks and through theo enings 22 and 32.

l As stated, t e forward disk 22 of the compound piston is prevented from rotating on the piston rod 23, being fixed thereon, and

said piston rod 23 and ltshead 23a are nonrotatably connected with the washer 27 by the projections 28. As shown in Fig. 29, the washer 27 is provided with a raised projection on its forward face'near its circumference, at ri ht angles to `the recesses 28, said forwar projection providing a thickened portion carrying a spllne 27". This spline may be integra-l with the washer 27, but, as. shown inFig. 29, it preferably vals comprises the T-shaped head/of a pin fitted and fastened in a radialhole drilled into said thickened portion. In the same plane which passes throu h 27 and the spline 2g, washer which itsover the cylindrical head 23a of the piston rod 23, has ltwo opposite grooves, see Fig. 29. The `ooves arenecessary merely for the assem ling of the washer 27 on said piston rod head 23 tov allow the washer to pass rearwardly on said head beyond the projections 28 thereon, whereupon a quarter turn of the washer 27 will bring the recesses 28a into the posi- Ition to receive said projections 28.

i As shown in Fig. 22, the spline 27" projects into a longitudinal groove 27b in the adjacent right-hand side Wall of the breech block guide 18, said groove 27b being also shown, by dotted lines, in Fig. 23. By this construction the Washer 27 is held against rotation and it prevents rotation of thie piston rod head 23a and of the piston rod 23; and, because the forward disk 22 of the compound piston is fixed upon thelrd 23, said disk also is prevented from rotating. For convenience of manufacture, the groove 27 b is-preferabl cut clean through the wall of the breech b o ck guide 18. ,'The integral rear wallxof the brake tube 21 rests against the rear plate 5 of the casa transverseslot 21h to which a screw driver Fig. 24.

the axis of the washer the central hole in thel lng, and is provided in its rear surface with applied `for rotating saidftube, see

In said integral rear wall (if the v 21 is Aalso provided a hole for filling the liquid chamber, said hole being threaded and closed'by a screw plug 30.

1 Connected with the liquid chamber and preferablyf-y located in the diaphragm 29 is a' safety valve'25, see Figs. 25, 33 and 36.

This `sanity valve consists of a conical valve head fitted to' close a valve seatwhich communicates with the liquid chamber and a guide 'stem which loosely fits into vthe central bore of a screw bushin which closes they forwardy .end of the ho e in the diaphragm. Between the rear 'of thel bushing and the front of the valve yhead a. yspring l is fitted, the tension .of vwhich keeps the valve closed under normal conditions of operation. However, should the' brake required forits proper operation, the safety valve willy be opened and enough of the vliquid will es'capeftol permitl the proper operation of the brake device. f f f y f Cut into the outer surface of the rear wall of the rotatable tube 21'near its ycircumference is an index mark pointingv outward, and in the rear Asurface 'of the stationary breech block guide 18, two short radial 'lines are cut, marked respectively o andy c rand spaced rapart slightly'more 'than 90, see

Figs. 24.-A and 7.

From the foregoing description ofthe construction of the liquid brake, itv will be*y seen that, by turning'the brake tube 21 in a f clockwise direction, see Figs. 7 and 26, the

' effectivey area of the openings permitting the i and yby yturningfsaid tube in a counter-clock'- liquidl to pass from one side to the other of the compoundpiston 22, 32 is diminished,

wise. f direction, the effective area of said openings is increased.4 This adjustment of the liquid brake provides for the proper braking action under widely varying conditions` of operation, such as wide differences in the angles of elevation of the gun and a broad range of temperature changes; it also permits the control, within limits, of the rate of ring of the gun when tiring automatically. g

For yieldingly holding the brake tube 21 after adjustlnent, a portion of the cylindrical surface has cnt in it shallow longitudinal serrations 21, see Figs. 24, 26 and 27, and a flat spring 34 seated in the breech block guide 18 is provided with an inward ,projection 34 the inner surface of which is similarly serrated, whereby the spring and the projection on it yieldingly keep said tube 21 from rotation.

As already stated the member 18 and the parts associated therewith are normally held in place by the rear cover 5. In order to prevent the parts from prematurely moving rearward as soon as the cover is removed a atch is preferably provided as shown in Figs. 24 and 43. A flat latch spring 19 is carried by the member 18 and its rear end is normally seated in a recess in the side wall of the casing. A hole 19a is provided in the casing adjacent the recess, and this allows inward pressure to be exerted on the spring to release it. The point of a bullet may be used for thisl purpose. When the latch 19 is released the member 18 and associated parts, including the barrel and barrel extension, may be removed. l Y v The accelerator 35 has the additional function .of locking the barrel and barrel extension in rearward posi tion'a gainst the tension of the spring 2() as illustrated in Fig. 13. For thisy purpose the accelerator is provided with rearwardly projecting lugs 3.5,which have ward and engaged the accelerator to release vit from engagement with ythe 'arm 26.l The sprm f yieldlngly hold the accelerator in one or the 34 already mentioned also serves to other vof its extreme positions.

In Fig. 4.5, the spring 34 1sv shown, detached, in a side viewfand in a rear end view.

f rel against the counterr recoil movement until 1 such time as the breech block has moved for,-y

The side view of the detached spring clearlyy y shows that it is curved, the shorter rear portion being bent outward, but the vlonger forward portion having'a double bend, its forward .end 34h being bentvinward; when in place in the breech block guide 18, said forward end rests in a shallow recess in the bottom of the accelerator 35, see Fig. 25. By this arrangement the spring 34 yieldingly holds the accelerator 35 in either of its two positions, shown in Figs. 12 and 13.

In Fig. l2, the breech block 17 is shown in its forward firing position to which it has been returned by the tension of a long reaction spring 36, said spring 36 being coiled around a guide rod 37 which isseated. in a longitudinal hole located in the right-hand side portion of the breech block near the top, said `hole, and rod extending entirely through said breech block so that the ends of the rod 37 protrude from the breech block in front and in rear. This lengthwise hole for the rod 37 is counterbored or enlarged from its rear end Ato a point near the forward end of the Vbreech block thus forming a shoulder against which the end of the spring 36 rests and transmits its tension in forward direction directly to the breech block 17, while the rear end of said spring 36 on the rod 37 rests against a shoulder formed by an enlarged head 37provided on the rod 37 near its rear en'd and transmits its tension in rearward direction through said head 37a to the rear plate 5.

The rear surface of said enlarged head 3T of the rod 37 is provided with a narrow central rib 37b and the inner surface of the rear plate 5 has cut in it a correspondingly nar- .row vertical groove extending downwardly through and out of said plate 5. This arrangement of the groove in the rear plate 5 plate is in its normal position, b the engagement of the rib 37b onthe ro head 37a 1n the groove in the rear late 5. Vertical hmovement of the rod hea 37a is thus pos1- tively prevented by the projection 37. After the rear plate has been upwardly withdrawn in the manner hereinbefore described,vthe guide rod 37 with its head 37a is held by the projection 37 resting against the rear ofthe hole in the .side wall of the breech casing 1 under the tension of the reaction spring-36, thereby preventing the rod 37 and the spring 36 from being projected rearwardly out of the breech casing. Such rearward ejection of said rod and spring would even be prevented should the breech block 17 happen to be at the rear and, therefore, the reaction spring 36 be under its maximum tension.

However, it is to be 'understood that normally the rear plate 5, is to be removed only when the breech block is in its forward position,v as then the reaction sprin 36 1s not under its maximum tension, so t at the rod 37, if then freed. will not be .thrown rearward with dangerous violence. In this forward position of the breech blockv 17, the lateral playtof the long reaction spring guide rod 37 and of the only partly compressed reaction spring 36 in their Aseat in the breech block 17 allows the rear end of the rod 37 and the projection. 37 thereon to be easily moved to the left suiiiciently to withdraw said projection from the hole in the breech casing l, after which the rod 37 and the spring 36 may be rearwardly removed. In contrast to the easy removal of the rod 37 and spring 36 with the breech blockfforward, their removal becomes so diicult as to be almost impossible when the breech block is in rear and the spring fully compressed. There are several reasons for this diliiculty. The maximum tension of the compressed spring 36 holds the projectionv 37 of the rod 37 very securely in its seat inthe sidewall of the casing, but in addition to this, the compression of the spring 36 within its lseat fin the breech block 17 causes .Y said spring to expand radiallyv so as to become almost rigid in said seat and thereby diminish the play of the rod 37 and its projection 37 so much that said projection cannot be moved out of its seat in the wall of as hereinbefore described.

the breech casing without the use of great force.

described hereinbefore as resting against the shoulder formed by'the counterbore in the breech block 17 and asl thus transmitting the tension ori' said spring directly to said' breech block; but in Figs. 12 and `1,4 lr have shown, merely for the purpose of assembly and disassembly, avstrong washer, which is inserted between said shoulder and the forward end ofthe spring 36 and which serves to transmit the tension of said spring to, the breech block. vA removablelateral projection- 37d ,is provided on the rod 37 forv ward of the washer and within the breech,

wardly 4far enough to allow said projection. to enter the counterbored -seat beyond the shoulder against which the washer rests, see Figs. 9,10, 16l and 19; In this condition the rod 37 with the spring 36, washer, and

projectionl 37d thereon may be rearwardly withdrawn from ythe breech block. In order to separate these parts, the projection 37d is removed from the rod and thewasher and spring are .dismounted in forward direction from the same.

For assembling, the spring 36y and the washer are remounted on the rod 37 and the projection 37d is replaced to hold them on the rod, yand then these arts together are replaced in the breech b ook and the projection 37d is entered into the lateral slot inthe forward portion 'of said breech block. With the breech block in the forward position in the breech casing l, the projection 37 is easily entered into the hole in the side wall of the breech casing where it is yieldingly held by the tension of the spring 36 This permits the rear plate 5 to be entered in the top of the casing 1 and Vmoved downward to its normal position, the lower ends of the two side walls of the groove` in the rear plate 5 being beveled to incline outwardly, Fig. 6, to readily slide over the rib 37 b on the rear end of the rod head 37 a, and the upper rear corners of the head 37 and the ribs 37b being beveled upwardly and forwardly for the same purpose, see Figs. 12 and 46.

Fig. 17 represents a rear endview of the breech block 17 and Fig. 19 a right-hand side elevation of the same, and `in bot-h of these figures is shown a slot 38 cut through The forward end of the spring 36`has been the right-hand side wall of the breech block suicient to insure clearance for the projection 37 c on the rod head 37 n when the breech block is in its rearmost position.

It will be understood that during the rearward movement ofthe breech block theV empty cartridge is ejected from the firing chamber anda cartridge to be fired is ext'racted from the feed belt. During the return forward movement of the breech block the extracted cartridge is moved into the firing chamber in position to be fired by the firing mechanism. The ejecting and extracting mechanism will hereinafter be described in detail but the description of the tiring mechanism will next follow.

The breech block 17 is provided with a longitudinal seat therein which is so located that its axis coincides with the prolongation of the longitudinal axis of the barrel.- Positioned in the said recess is a iring pin made i'n two parts 39, 39, and its main spring or firing spring 40, see Figs. 13, 14, and 15.

This two-part firing pin and co-operatin parts are shown, detached and on an enlarge scale, in Figs. 38 to' 42, inclusive. In Fig. 38

are shown the main spring or firing spring' and its co-operating abutments. Fior. 39 shows the two-part firing pin assembled, in a. front end view, in a rear end view, and in a sideview, in said side view, the rear tubular part is shown in a vertical longitudinal section. Beneath said longitudinal section are also shown four taken, respectively, at the places of the longitudinal section directly above them. Figs. 40 and 4l show, respectively, the two parts of the firing pin separated from each other. Fig. 41 shows a front view, a side view and a rear view of the forward part 39 of the firing pin. Fig. 4Q shows a front end view, a top view, and a rear end view of the tubular rear part of said iiring pin, the inner bore of which is indicated in dotted lines inv said .top view, but the vertical longitudinal slot 39b is clearly shown -in full lines; also indicated in dotted lines is the horizontal transverse hole for receiving the vpin 43, as clearly shown in Figs. 38 and 39, to serve for the abutment of the forward end of the main spring 40. Fig. '42 `represents also a front view of the rear tubular part of the firing pin -in which the transverse pin 43 is more clearly shown as seated in the hole provided for it in saidpart.

In assembling, the main spring 40 is inserted from the front into its seat in the rear tubular part 39 of the firing pin and is then l fixed therein by placing the transverse pin 43 in front of it. Forward of said pin 43, the bore of the tubular rear part 39 is, for some distance, increased in diameter to correspond with the shouldered rear end of the forward part 39 of said firing pin, and the top portion of the tubular part is cut away upwardly, thereby providing the opening for transverse Sections entering said shouldered end of the part 39 into the tubular part 39 to connect and interlock these two parts of the firin pin longitudinally. When the two-part ring pin,

in this condition, is inserted into i'ts longltudinal seat in the breech block 17, the inner surface of said seat lits over the shouldered end of the forward part 39 and thereby prevents the same from moving transversely and the two parts of the firing pin from separatmg.

As clearly shown in the transverse sec` tions which are parts of Fig. 39, and in the top view, Fig. 40, the vertical slot 39b is only as wide as is necessary to admit into it the pin 45 clearly shown in Fig. 38, and both the pin 45 and the slot 39b are considerably smaller than is the bore or seat for the main spring 40 in the tubular part 39'* of the' firing pin. The forward end of this vertical slot 39"'lies somewhat forward of the rear end of said bore'or seat, and said slot extends from there rearward to a point some distance forward of the rear end of the Iiring pin. Said rear end of the tubular part 39 of the firing pin and the forward end 'of the same are both increased in dimension to it the seat in the breech block 17, but the extreme rear end is neither tubular, nor cut away upwardly, nor slotted, but its under side is iiattened and has an upward recess cut in it thereby forming the cooking shoulder slightly forward of the rear end, for its engagement b the sear.

The pin 45 as at its upper end an integral arm 45, and. with said pin and arm placed in the breech block 17 said arm lies in a central vertical longitudinal recess in the top of 'the rear portion of said breech block; said pin and integral arm may be turned, thereby moving the projection 45. see Fig. 38, to the left to cause it to enter into a lateral recess 17". see Fig. 17, thus locking the pin and arm against .vertical movement.

The cooking lever 42 is pivotally mounted in said vertical recess o'n the removable transverse pin 42a, shown detached in Fig. 47

The head of said pin is approximately triangular in sha e and is located within a recess provid for it in the left-hand side of the breech block, as shown in Figs. 12, 13 and 15. The upper cooking' lever arm' 42 lies to the right of the integral arm 45 thereby preventing movement of the latter in that direction. which would withdraw its projection 45 from the recess 17 b: the lower arm of the cocking lever projects downwardly in'- to the vertical slot 39 in the firing pin. A 'projection 45" on the right-haynd side of the integral arm 45'. see Fig. 38, lies, when these parts are assembled in the breech block, in the path of the cocking lever 42 and thus limits the rearward movement of its upper arm.

The Sear 41, shown detached in Fig.'18

' ride over it an'd depress the sear, after which ,FigS. 7 8, 13, 14, 15 and 17, is slidably mounted in a. central vertical seat at the rear end of the breech block. At its lower end. said Sear has a forward extension 41 with an upward projection at its forward end; this upward projection is beveled at the front to permit the rear end of the irlng pin to its rear surface engages the cooking shoulder of the firing pin to hold the same in cocked position until the sear 4l is depressed. In the flat lower surface of the sear an upward recess is provided to receive the upper end of the short helical sear spring 44, the lower end of said spring44 resting in a similar recess provided for it in the breech block 17 under the seat of the sear, whereby the sear spring 44, when in its seat, yieldingly holds the sear 41 in its raised position. The upward movement of the sear 41 under the tension of its spring' 44 is limited by a shoulder 41c in the front surface of the sear meeting the underside of the integral arm 45% The length of the sear 41 permits its vertical operation without interfering with the cockinglever; but, on its right-hand side, said Sear 41 'carries a narrow u ward projection 41b which serves for the epression of the sear by the trigger mechanism.

The trigger mechanism for actuating the sear is located above the path of movement of the breech block. 0n'e of the advantages of the location is that it leaves the space below the path of movement of the breech block available for the mechanism for'absorbin the energy of recoil as already describe. l

As hereinbefore described, the trigger 9 has a forward and downward extension adapted, when raised by the depression of the outside rear portion of the trigger, to

actuate the sear through a suitable connecting member. This member is shown as being 'a lever 46 pivotally supported from the top plate of the casmg. This lever is of considerable length and extends forward far enough to transmit the movements of the triggerl 9 to the sear 41 when the breech block v17 is in the forward position. This lever 46 is pivotally attached near its center to the fixed lug 47 projecting downward from the top plate 4. of the casing by the pivot pin 46, The pin passes transversely through said lever 46, and through the fixed y lug 47 and out through the left-hand side plate of-the casing 1, as clearly shown in Figs. 1 and 7. The pin 46a has on the outside of said side late anintegral handle extending real-war ly and downwardly when it and the pin 46a are in ,their locked position. The handle is of uniform width, but Suliciently thin to be flexible, and carries at its end a slight'inward projection which engages in a corres onding recess in the outer surface, of the side plate of the breech casing thus yieldingl holding the pinand handle, in their locke position. On the inside of the side plate, the pin 46B carries a short spline, the radial center line of which'A coincides with that of the handle; at an angle preferably of 90 from the. position of thev handle and pin shown in Flg. 1, a4 roove is cut in the side plate of'the breec casing corresponding in width and depth with said spline on the pin 46a. By this arrange- 'ment, the pin ,and handle are yieldingly locked in position when the handle extends rearward,y while, with the handle and pin turned until the handle extends forward. they are unlocked and may be withdrawn from the breech casing, thereby releasing the trigger lever 46, which may then be removed downwardly from its seat in the breech casing. Q-

The cooking lever 42, above its central part, its pivot and its lower arm, extends upward and projects a considerable distance from the top of the breech block 17. The right-hand Asurface of the fixed lug 47 de- `pending from the top plate 4, is perfectly plane and the trigger lever 46 rests on this plane surface. However, the under side of ,said lug 47 has just in rear of its front end a downwardly projecting shoulder, and in `rear of it an opening which is produced by a recess 47 cut into the right-hand surface of said lug 47, and laterally of a depth slightly greater than the thickness of the cooking lever 42. The forward and rear walls ofl this recess 47 a incline, respectively, in forward and upward direction and in rearward and upward direction, and, at their intersection with the under side ofthe lug 47 produce said opening and the shoulder in front of it.

When the breech block is moved bythe position to the rearwardly inclined position,

see Fig. 12.

-By this arrangement, the lower arm of the `cooking lever is forwardly removed from its contact with the cocked firing pin and leaves Said firing pin held cocked solely by the Sear 41; therefore, if then the trigger is depressed, a shot is fired.

On the now following rearward opening` movenent of the breech block 17 the cocking lever is carried withI it and during the first part of such movement-, the upper end of said cocking lever is, by reason ofits engagement with the rear wall of the recess 47L in the fixed lug 47, moved from the rearwardly inclined position to the forwardly inclined position, thereb again cooking the firing pin.` The lever is ept in this position during the further rearward umovement, and during thel greater portion of the suceeedfng forward movement of the breech block, hy the piane under side of said lug 47 in rear of the opening therein. Thus the. entire cooking operation is concluded'. y

When the parts are in the position shown in Fig. 12, with the breech blockclosed, a single shot may be tired by depressing the trigger 9 and atl once releasing it; thereby the scar is lowered by the lever 46 and it releasesthe firing pin, which tires one shot.`

By the resulting recoil, the parts are changed from their positions shown in Fig. 12 to their positions shown in Fig. 13, with the breech open, from which position they are at once returned forward again by the reaction spring 36, see Fig. 12. During the last of this forward movement of the sear 41, being yieldingly held by its spring in its raised position, engages and lifts the forward end of the lever 46'and lowers its rear end ready to be again operated by the trigger 9. j

If it becomes necessary to fire, instead lof single shots, a volley, that is numbers of shots in rapid succession, the operation is as follows: the trigger is depressed and kept;`

depressed, thereby the rear end of the trigger lever is raised and kept raised and the forward end of said trigger lever is kept in its lowered position and in the path of the top of the sear. In order toA insure that the sear will not be lowered until the very last of the forward movement of the breech block closing the breech, the trigger lever 46 is provided at the forward end with a' projection inclining in forward and downward direction, which serves to depress the sear at the proper time. These operations are automatically repeated, as long as the trigger is kept depressed and cartridges are supplied.

' In the embodiment of the invention shown in the drawings, the cartridges are fed into a horizontal transverse feed channel provided in the front block 2 of the breech casin above the barrel seat therein, and, since this channel is closed at thc top only bythe hinged cover 4a hereinbefore described, by raising said cover a cartridge. belt is readily placed in position in the gun or removed therefrom as required. With the loaded .cartridge belt placed in Aposition and the cover closed down thereon the .belt 'is fed with a step by step movement preferably from the left to the right side in the usual hole, then said extractor 48 is tn'rne `manner linmachine guns of this class, to

bring the cartridges successively to a central position over-the barrel.

guided for transverse reciprocating 'movement 1n the under side of the-to cover 4*.

This movement 1s. l effected by the feed slide with its depend ing pawl, said slide being supported and 70.-

vA stop is provided on the leftand side .i

jecting stud, which normally extends into.

the lcam groove 57 in the top of the breech block 17, see Figs. 12, 13 and'14, whereby the longitudinal reciprocating movement of said .breech block produces a lateral movement of said lever and this causes'a transverse reciprocating movement of said slide -4 55, thus moving the cartridge belt stepwise through the feed channel.

The feed extractor 48 is pivotally attached to the left-hand side 'nf the breech block 17 some distance in rear of the face of the same, and extends forward beyond said face, see Figs. l2, 13 and 15. At its forward end, said feed extractor 48 carries on its right-hand or inner side a lateral projection extending inward some distance beyond the longitudinal axis of the breech 'block 17'.

Its rear end is party-circular and has extending beyond it a projecting concentric rib, a corresponding under-cut recess in the rear side of the seat in the breech block being provided for said rib. By this 'construct-ion, the feed extractor 48 may be readily attached to and. detached-from the sideof the breech block 17, which, for receiving said feed extractor 48, is reduced Ain` width andforms a shoulder in rear of the seat, partycircular with an under-cut recess. For mounting and attaching the feed extractor 48, its pivot is partlyinserted into the ivot u ward until its body stands at an angle iff substantially 90 above the top of the breech block, then pivot and body of the extractor 48' may be fully pressed inwardly home and turned to their normal position, by which they will be properly mounted on and locked to the breech block, and said extractor 48 will extend forward beyond the face of said breech block. The lower side of this inwardly projecting part of the feed extractor`48 is provided with a downward projection 48, the lower 'edge of which is curved to correspond substantially with the curvature of the cartridge just forward of its head.

Just before the breech block 17 reaches the end of its forwardclosing movement, the rounded to of the head of the feed extractor 48' as been raised against the flat spring .above it attached to the top cover 4, and the depending part 48a of said feed extractor is brought into contact with the top of the head of the cartridge in the feed beltcentral abovethe barrel. Then the last of the forward movement of the breech block causes the upper'edge of the central cartridge to co-operate with the forward, rearwardly and downwardly, inclined, surface oft-he projection 48, thereby allowing said projection to pass over the cartridge head. Thereupon the top of the feed extractor 48 will be depressed by the spring 50 and the projection 48a will be entered into the groove 'in the cartridge forward of its head, the

projection, being inclined downward and rearward thus secures a firm hold u on the cartridge. By the ensumgrearwar. movement of the breech block, the cartridge is' withdrawn from the feed belt; at the very first part of such movement, the feed extractor' 48 is kept down with its projection 48 extended into the groove forward of the cartridge head, by the spring 50, then th`e rounded top of said'feed extractor 48 is carried under the horizontal forward portion of the depending feed extractor cam 5l, thereby positively keeping said extractor from upward movement. With the further" rearward movement of said breech block, the top of the feed extractor is carriedbelow the downwardly and rearwardly` inclined under side of the cam 51,V which serves, during the continued rearward movement of the breech block and feed extractor,

A' I' to partly depress the feed extractor, and the cartridge to the position in'which theyare shown'in Fig. 13. In this position, the cartridge head and groove have been introduced into the vertical fiange-way von the front face of the breech block, the top opening of which is flaring to facilitate the entra-nce of them. i

It must be understood that during the entire operations of the gun mechanism hereinafter described, the head and the groove of each cartridge7 after it has been drawn out of the feed belt and has been introduced into the flange-way, remains firmly and securely held in the grasp of said ange-way and even after each of the cartridges has been tired, the head and groove ofits emptied shell still remain held in the flange-wav till, at last, it is downwardly ejected from the gun.

Having now described the longitudinal rearward movement of the breech block and also lits return movement forward, there remains, to be explained the difference-of action of the feed extractor during itsforward movement, from its action during its rearward movement.

This difference in the action of the feed extractor 48 during its forward movement is mainly due -to three features of construction, two of which are entirely novel important improvements.

When in position in the breech casing, see

Fig.` 1, the threaded portion ot' the stud 52a extends beyond the outside surface of said breech casing 1, and on this outside end of the stud is' fitted a nut which removably fastens the switch lever 52 in its place, without, however, interfering with the free vibrating movement of lever, stud and nut, because the stud, between its shoulder and the surface of the switch lever, is slightly longer than the thickness of the side wall of the casing. Said switch lever 52 is clearly shown, detached, in a side elevation and infa top View, in Fig. 5 above Fig. 1.

(Jn the left-hand or outer'surface of its rear armV the switch lever 52 has a project-A ing longitudinal rib 52b below its upper edge, and, in the inner surface of the side wall of the casing, a recess is cut into which Said rib 52 enters; besides making room for said rib 52", said recess also serves for the reception of a two-armed spring 53, the longer lower arm of which rests upon the horizontal lower side of said recess, and the shorter upper arm of the spring bears upwardly against ino the under side of the rib 52", 'see Figs. 1

end of the switch lever 52 a flat piece 54 is fixed by two rivets to the inside surface of the side wall of the breech casing, therefore lying in the same vertical plane with the switch lever 52; the rear surface of said piece 54 inclines upward and forward, see Fig. 1.

On its left-hand or outer surface, the pivoted feed extractor 48 has, near its head, an integral lateral projection 48h, see Figs. l2, 13, 15, 9 and 10; this projection is more clearly represented lin Figs. 21 and 20, where the feed extractor 48 is shown, detached, and on a much enlarged scale. projection 48" is o'f considerable horizontal length, narrow -inheight, and projects laterally from the surfaceof the feed extractor almostto the inside surface of the side wall of thc breech casing, thereby insuring its engagement by the switch lever 52 and the piece 54.

During the last'of the rearward movement of the breech block, the head of the feed This integral extractor 48 is depressed, and carried rear- :lle

so depressed, the lateral projection 48" thereon engages the top of the rear arm of the switch lever 52 to .lower it against the action of its spring 53 which returns the lever again to its normal position after said projection has been carried rearwardly beyond said lever. On the succeedingl forward movementof the breech block, the lateral projection 48b on the head of the feed extractor strikes the downward and forward inclined end of the lever 52 and said feed extractor head is thereby depressed toits. lowest position, indicated in Fig. 10, with the cartridge substantially in line with the axis ofthe barrel. By the continued forward movement of the breech block/and feed extractor, the integral lateral projection 48b on said extractor is carried through the opening beneath the straight lower edge of the switch lever 52 and above the straight` top surface of the barrel extension 15.

' Thereby the feed extractor head is kept in its lowest position and the cartridge is be" ing inserted into the barrel ynearingr the last of the forward movement, the front end of the lateral projection 48b lon the feed extiac'tor head strikes against the upward. and` forward inclined edge of' the fixed piece 54, whereby said feed extractorhead-l is raised.

'lVhile the feed extractor head is thus be-Y ing' raised, the rear end of the integral lateral projection `48b engages the under side of the forward arm of the switch lever 52, and thereby also raises said lever arm against the tension of the spring 53, until, bythe last of its forward and upward movement, the rear end of said projection 48b is carried above andv forward of said lever arm and thus releases said lever arm, which is at once returned to its lowered normal position by ythe spring 53. By this return of the lever arm. it assumes a position below the irear end of the integral lateral projection 48" of the feed extractor, and thereby closes the opening between the fixed piece 54 and the forward end of the lever arm in such a manner that the integral lateral ,projectionc 48b cannot possibly return downward into said opening, but must move above the up-` per edge of theswitch lever during the ensuing rearward movement. i

A vertical longitudinal slot is cut in the head of the feed extractor 4S some distance below its highest portion and laterally some distance to the left of the downward projection 48a in the vertical plane through the axis of the gun barrel, hereinbe ore referred to, said slot forming the seat for the upper portion of the depending ejector 49- This upper portion of the ejector is considerably thinner than the width of said slot, it being clearly shown in Fig. 21 that-the left-hand side of said 'upper portion is reduced in thickness, down to a shoulder formed 0n said left-hand side of the -ejector below its seat' in the feed extractor head; 'I Said ejector 49 is pivotally mounted in Asaid seat on a transverse pin 49, which passes through -said feed extractor head from the left to .the right side thereof. vThe said pin 49 is shown in Figs. 21 and-20, with a. thin head seated in a recess provided for it, and at its other end s lit for some distance, so that it may be rea ily placed in position inor removed' from said'feed extractor head, but is frictionally held in place therein. The hole in the' ejector 49 which receives the pivot pin .49'is slanting and the bottom of said hole is inclined downward towards the left to allow the lower end of the ejector` to 'swing to the left side. The said ejector is normally kept yieldingly in its substantially vertical position by a small helical spring 497 seated in the head of the feed extractor 48 and bearing on the ejector in rear of the pivot pin 49. While the ejector 49 is shown in Fig. 21 in its laterally substantially vertical position, in Fig. 16 'it is represented with its lower end moved tov tween the heads of two cartridges infrontof it, to wedge said cartridge heads apart, and thereby to insure that the downward projection 48' of the feed -extractor will grasp and, .on the ensuing rearward movement, withdraw only one of said cartridges from the belt.

At its lower end the ejector 49 has an inward or right-hand projection, see Fig. 16, which extends laterally beneath the cartridge when the same is grasped by the feed extractor, and below sald inward projection, thel vend of the ejector is inchned downward and to the left, until said incline meets the vertical longitudinal plane through the center of the ejector. On the left side of said plane the end,4 of the ejector 1s When the head of the feed extractor 48 and the ejectorl 49 lare being lowered from the position shown in Fig. 9 to the position shown in Fig. 10, if the ejector happens to be swungr outwardly as shown in Figs. 9 and 16, the rounded outer end of said ejector strikes the inclined upper corner 15HL on the left-hand side of the central ejection opening through the barrel extension 15, whereby the end of the ejector is forced' inward and kept in that position until, during its flu-ther descent, the end of the ejector strikes the empty cartridge shell and expels it from the gun, see Fig. 10. In Figs. 9 and is shown, forward ,of the inclinedupper laction spring l36 and the guide rod 37 are 65 corner l5", a lateral and vertical recess in the left-hand wall of the ejectionopening in the barrel extension 15. The recess allows the ejector, on its upward movement, to swing -laterally suliiciently for allowing its inward projection to pass upwardly by the body of the cartridge.

For the initial opening of the breech of the gur, the breech blbck must be once drawn to the rear; for this purpose the usual handle, such as 59, is removably attached to the breech block, anda longitudinal slot registering with said handle is cutithrough the right-hand side plate of the breech casing 1 of a suiiicient length to permit the necessary full rearward movement of the handle and breech block. Said handle 59 'has a cylindrical stem which is fitted into a corresponding seat extending a consider\ able distance into the body ofthe breech block. Inside of the breech casing, said handle has a concentric circular collar which occupies a corresponding recess in the side of the breech block, and, as said collar has a diameter much larger than the width of the slot, itprevents the detachment of the handle 59 from the breech block. At' a point some distance forward of the rear end of said slot, concentric segmental recesses of the same diameter as the collar on the handle are formedin the ed es of the slot, thereby providing at that o1nt an opening for, at will, attaching sa1d handle to the breech block or detaching it therefrom. Ac-

cidental. detachment of the handle at this' place during the automatic operation of the gun is impossible, because Such detachment would require a pause or stoppage in the longitudinal movement of the breech block and handle on account of the close fit of the collar in said opening and the necessary transverse movement of the handle; whereas, the breech block and the handle are automatically moved rearward at such a rate of speed that nothing like a pause could pos-v sibly take place until they reach their rearmostposition. During the automatic for- .Ward movement under the tension of the reaction spring, accidental detachment of the handle is likewise impossible.

The procedure to be followed in disassembling the gun will now be described.

It will be understood that the handle 59 may be. at will, detached from the breech block without previously removing the-rear plate 5 from the casing; but for the insertion into `or withdrawal from the breech casing of the lengthwise movable members of the breech mechanism, 1t 1s, of course, necessary previously toremove said rear plate.,

Preparatory to the withdrawal of vthe breech bloc-k, the same is first moved to'its forward position in the casing, then the rewithdrawn from the breech casing.

The top cover 4a is then raised and the breech block is pushed rearwardy out ofthe casing.

The combined breech block guide and energy absorbingmechanism is released by pnessing the spring latch 19 inward as already described. With fthe mechanism thus released for rearward'removal, pressure is .exerted against the muzzle of the barrel and thereby the barrel 13, the barrel extension and the breech block guide 18 with asso-4 ciated parts are pushed rearwardly out of the breech casing-where they may be'properly adjusted and, thereafter, may be returned to their. position in the breech casing, in

which the stop spring 19 will again holdA them.

In this position and with the rear plate 5 still removed, the rear face of the brake tube 21 is uncovered and, by removing the plug 30, the brake tube may be filled with liquid and then closed again. Should the brake mechanism require adjustment this may be accomplished by turning the tube 21 as a1- ready described. f

With the foregoing description of the con- .struction and'operation of the parts of the gun, the operation of the gun as a whole ma be readily understood. f

i 'ter a filled cartridge feed belt has been placed in position in the feed channel and the top cover 4a closed, thereby insuring the transverse movement of the'feed belt, the breech block is once moved by hand to the rear, thereby withdrawing from the feed belt the first cartridge and, at last, lowering it to the axis of the barrel for its insertion therein, on the ensuing forward movement of. the breech block by the tension of the reaction spring36.

If the gun has been previously fired and an empty shell has remained in the-chamber of the barrel, said shell` is' withdrawn and, by the downward movement of the ex'- tractor is ejected from the gun casing; On depressing the trigger 9 and releasing the same, the first cartridge is fired and the operation of the bre-ech mechanism is then au'pomatically repeated thereby seat-ing another cartridge in the barrel ready for firing.

While a specific embodiment of what is considered the best reduction of the invenf tionto practice has been disclosed in the specification, it is to beV understood that various changes i-n the form and arrangement llt) of parts may7 ,be made without departing from the spirit of the invention.

What I claimA and desire tor secure byLetters Patent is: -l

tion of 'a breech' casing, a recoiling member supported and guided yfor longitudinal 1. vIn an automatic firearm, the combina- 

